1. Department of Neurobiology & Behavior, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 852-8523, Japan
2. Department of Biological Sciences, School of Science
3. Laboratory of Animal Resources, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan